The present embodiments relate to a device and to a method for safely operating the device.
Devices (e.g., computer platforms) that are integrated into a technical context may have a safety apparatus. The safety apparatus may be embodied as a single-chip safety microcontroller and acts as a trust anchor (e.g., as a superordinate entity) that is trusted without this trust having to be derived elsewhere. Safety apparatuses that function similarly to a chip card are generally known.
Such a safety apparatus provides the device with basic functions for implementing cryptographic methods. The device may be operated safely with the basic functions. This includes, for example, safe behavior, enabling, deriving, and outputting of cryptographic parameters (e.g., of cryptographic keys or cryptographic checksums; digital signatures or message authentication codes or of response values of a challenge response authentication protocol).
These basic functions are available after the safety apparatus has been enabled by enabling information. The enabling may be carried out by a control apparatus (Central Processing Unit, CPU) via a common physical interface. This physical interface is, however, not necessarily protected against tampering. The enabling information may therefore be read out in plain text on the CPU.
DE 10 2011 002 706 B4 discloses preventing the enabling of the safety apparatus by the control apparatus when attempted tampering is detected.